This invention relates to a cable take-up device for an electric drive vehicle. There have recently been conducted mechanizations and eliminations or reductions of labor in civil works and in loading and unloading operations, etc. Particularly in a case wherein there is likelihood of causing undesirable problems in the working environment such as air pollution, noise, etc. as in underground digging work in a tunnel or mine, below-deck operations in a vessel, indoor work, etc., an electric drive vehicle is broadly adapted to obviate these problems.
Since such an electric drive vehicle consumes great power in doing the aforementioned work, it does not use a charging system but directly employs a commercial power supply in order to eliminate loss in the operation time of the vehicle caused by battery charging and thereby to improve its working efficiency and to reduce the working cost. Therefore, as this vehicle uses a system which directly connects a feeder cable to the power supply, it becomes a very important problem to properly handle this feeder cable so as to enhance its working efficiency.
This invention contemplates obviating the above described disadvantages of the conventional electric drive vehicle and to efficiently solve the problem of handling the feeder cable connected to the electric drive vehicle. To this end, its mounts a cable take-up device at the rear of the vehicle, always controls a winding angle of the cable constant with respect to a plane perpendicular to the horizontal or absolute plane in the longitudinally axial direction of the vehicle of the cable take up onto the cable take-up device, removes abnormal tension, bending or twisting of the cable under any condition such as in forward or reverse running and speed change and steering controls, etc. of the vehicle, prevents the deterioration of strength and breaking of the cable and, in addition, prevents damage to the cable due to being run over by the vehicle or due to slackness and overlapping of the cable as it is taken up onto the cable take-up device owing to the excessive looseness of the cable, and performs safe and efficient operation of the vehicle.
There has been was disclosed U.S. Pat. No. 3,861,505 a system which adds a constant torque always to a cable take-up drum of an electric drive vehicle and which cannot consequently keep the rotation of the take-up drum current with the operations of the vehicle at abrupt acceleration and deceleration of the vehicle with the result that excessive tension is added to the cable to cause the cable to be broken or to be excessively slackened resulting in looseness and overlapping of the cable on the taken-up drum. Further, as the torque motor always consumes electric power for adding a torque to the cable, the motor must be of a large type and requires a blower for cooling itself.